Quantitative Determination of Phase Content in Multiphase Polymers by Combining Spin-Diffusion and CP-MAS NMR

Abstract

We present a new approach to determine quantitatively the phase content of multiphase polymers by applying a spin-diffusion pulse sequence (filter) prior to cross-polarization (CP) in a 13C-CPAS experiment. The technique is exemplified for two rather different polymer systems, a high-density polyethylene (HDPE) and four styrene−isoprene diblock copolymers, all of known phase contents. In principle, the technique should be applicable to any multiphase system in which spin-diffusion between different regions/phases exists and where the magnetization of phases can selectively be filtered out.

Fine grinding of thermoplastics by high speed friction grinding assisted by guar gum

“…LDPE, HDPE and PP of both 2000–710 μm and 710–45 μm had similar line shapes. The 31.4 ppm shift could be deconvoluted into 30.2–30.6 and 31.4 ppm in LDPE and 30.5–30.6 and 31.4–31.5 ppm for HDPE as the former arises from amorphous phase and the latter from crystalline phase 38 . FTIR‐ATR bands (Figures S7–S10) were identical for all four thermoplastics and of different particle sizes.…”

“…13 C shifts of PLA near 16.1, 68.8, and 168.7 ppm were assigned to methyl, methine and carbonyl carbons 37 . 13 C shifts of LDPE and HDPE near 13.5 and 31.4 were assigned to methyl and methine carbons 38 . 13 C shifts of isotactic PP at 20.48, 25.02, and 42.84 were assigned to methyl, methine and methylene carbons 39 .…”

Influence of grape marc extract on tuning the intermolecular interactions in the high‐density polyethylene

“…[23][24][25][26][27] Information about the sample heterogeneity and the size of different domains/components at the nanoscale can be obtained by studying the time dependence of the magnetization transfer throughout the sample generated by spin diffusion. 10,13,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] Spin diffusion represents a dynamic process driven by the magnetic dipole-dipole interaction, and it does not involve any physical movement of spins. Experiments based on spin diffusion can provide insight into the structural and morphological properties of complex heterogeneous systems owing to the dependence of the spin diffusion process on the strength of dipolar coupling.…”

“…13 Spin diffusion has been used to study the domain structure in block copolymers, polymer blends, and other heterogeneous polymer systems. 21,[23][24][25][26][27][28]30,[34][35][36][37][38][39]42,43 The mixing level of the structural constituents (miscibility) will affect the rate of spin diffusion yielding information about their size. The greater the mixing, the stronger the interaction between components.…”

“…The study of morphology and phase structure at the sub‐micron levels of polymer composite materials is of both scientific and practical significance 23–27 . Information about the sample heterogeneity and the size of different domains/components at the nanoscale can be obtained by studying the time dependence of the magnetization transfer throughout the sample generated by spin diffusion 10,13,23–41 . Spin diffusion represents a dynamic process driven by the magnetic dipole–dipole interaction, and it does not involve any physical movement of spins.…”